At the
Partition of Triparadisus
in 321 BC, Seleucus was appointed Satrap of Babylon
under the new regent Antipater. But almost immediately, the wars between the Diadochi resumed and
Antigonus[D]
forced Seleucus to flee Babylon. Seleucus was only able to return to Babylon in 312 BC with the support of Ptolemy. From 312 BC, Seleucus ruthlessly expanded his dominions and eventually conquered the
Persian
and Median
lands. Seleucus ruled not only Babylonia, but the entire enormous eastern part of Alexander's empire.

Seleucus' victories against Antigonus and Lysimachus left the Seleucid dynasty virtually unopposed in
Asia
and in Anatolia. However, Seleucus also hoped to take control of Lysimachus' European territories, primarily Thrace and Macedon itself. But upon arriving in Thrace in 281 BC, Seleucus was assassinated by
Ptolemy Ceraunus, who had taken refuge at the Seleucid court with his sister
Lysandra. The assassination of Seleucus destroyed Seleucid prospects in Thrace and Macedon, and paved the way for Ptolemy Ceraunus to absorb much of Lysimachus' former power in Macedon. Seleucus was succeeded by his son
Antiochus I
as ruler of the Seleucid empire.

Seleucus founded a number of new cities during his reign, including
Antioch
(300 BC) and in particular Seleucia on the Tigris
(ca. 305 BC), the new capital of the Seleucid Empire, a foundation that eventually depopulated Babylon.

Seleucus was the son of
Antiochus. Historian
Junianus Justinus
claims that Antiochus was one of Philip II of Macedon's generals, but no such general is mentioned in any other sources, and nothing is known of his supposed career under Philip. It is possible that Antiochus was a member of an upper Macedonian noble family. Seleucus' mother was supposedly called
Laodice, but nothing else is known of her. Later, Seleucus named a number of cities after his parents.[2]
Seleucus was born in Europos, located in the northern part of
Macedonia. Just a year before his birth (if the year 358 BC is accepted as the most likely date), the
Paeonians
invaded the region. Philip defeated the invaders and only a few years later utterly subdued them under Macedonian rule.[3]
Seleucus' year of birth is unclear. Justin claims he was 77 years old during the battle of Corupedium, which would place his year of birth at 358 BC.
Appianus
tells us Seleucus was 73 years old during the battle, which means 354 BC would be the year of birth. Eusebius of Caesarea, however, mentions the age of 75, and thus the year 356 BC, making Seleucus the same age as
Alexander the Great. This is most likely propaganda on Seleucus' part to make him seem comparable to Alexander.[4]

As a teenager, Seleucus was chosen to serve as the king's
page
(paides). It was customary for all male offspring of noble families to first serve in this position and later as officers in the king's army.
[2]

A number of legends, similar to those told of Alexander the Great, were told of Seleucus. It was said Antiochus told his son before he left to battle the Persians with Alexander that his real father was actually the god
Apollo. The god had left a ring with a picture of an
anchor
as a gift to Laodice. Seleucus had a birthmark shaped like an anchor. It was told that Seleucus' sons and grandsons also had similar birthmarks. The story is similar to the one told about Alexander. Most likely the story is merely propaganda by Seleucus, who presumably invented the story to present himself as the natural successor of Alexander.[2]

John Malalas
tells us Seleucus had a sister called Didymeia, who had sons called Nicanor and Nicomedes. It is most likely the sons are fictitious. Didymeia might refer to the oracle of Apollo in
Didyma
near Miletus. It has also been suggested that
Ptolemy (son of Seleucus)
was actually the uncle of Seleucus.[5]

Seleucus led the Royal Hypaspistai
during Alexander's Persian campaign.

In spring 334 BC, as a young man of about twenty-three, Seleucus accompanied Alexander into Asia. By the time of the Indian campaigns beginning in late in 327 BC, he had risen to the command of the élite infantry corps in the Macedonian army, the "Shield-bearers" (Hypaspistai, later known as the "Silvershields"). It is said by Arrian that when Alexander crossed the
Hydaspes river
on a boat, he was accompanied by Perdiccas,
Ptolemy I Soter,
Lysimachus
and also Seleucus.[6]
During the subsequent Battle of the Hydaspes
(326 BCE), Seleucus led his troops against the elephants of King Porus. It is likely[original research?]
that Seleucus had no role in the actual planning of the battle. He is also not mentioned as holding any major independent position during the battle, unlike, for example, Craterus,
Hephaistion,
Peithon
and Leonnatus
– each of whom had sizable detachments under his control.[7]
Seleucus' Royal Hypaspistai
were constantly under Alexander's eye and at his disposal. They later participated in the Indus Valley campaign, in the battles fought against the Malli
and in the crossing of the Gedrosian
desert.

Seleucus took his future wife, the
Sogdian
princess Apama
(daughter of Spitamenes), with him as his mistress into India, where she gave birth to his eldest son and successor
Antiochus I Soter
(325 BC). At the great marriage ceremony
at Susa
in the spring of 324 BC, Seleucus formally married Apama, and she later bore him at least two legitimate daughters (Laodice and Apama) and a son (Achaeus). At the same event, Alexander married the daughter of the late Persian King
Darius III
while several other Macedonians married Persian women. After Alexander's death (323 BCE), when the other senior Macedonian officers unloaded their "Susa wives" en masse, Seleucus was one of the very few who kept his, and Apama remained his consort (later Queen) for the rest of her life.[8]

Ancient sources mention Seleucus three times before the death of Alexander. He participated in a sailing trip near
Babylon, took part in the dinner party of
Medeios the Thessalian
with Alexander and visited the temple of the god Serapis.[citation needed]
In the first of these episodes, Alexander's diadem
was blown off his head and landed on some reeds near the tombs of Assyrian kings. Seleucus swam to fetch the diadem back, placing it on his own head while returning to the boat to keep it dry. The validity of the story is dubious. The story of the dinner party of Medeios may be true, but the plot to poison the King is unlikely.[clarification needed
insufficient details and context]
In the final story, Seleucus reportedly slept in the temple of Serapis in the hope that Alexander's health might improve. The validity of this story is also questionable, as the Graeco-Egyptian Serapis had not been invented at the time.[9]

Alexander the Great died without a successor in Babylon on June 10, 323 BC. His general
Perdiccas
became the regent of all of Alexander's empire, while Alexander's physically and mentally disabled half-brother Arrhidaeus was chosen as the next king under the name Philip III of Macedon. Alexander's unborn child (Alexander IV) was also named his father's successor. In the "Partition of Babylon" however, Perdiccas effectively divided the enormous Macedonian dominion among Alexander's generals. Seleucus was chosen to command the
Companion cavalry
(hetairoi) and appointed first or court
chiliarch, which made him the senior officer in the Royal Army after the regent and commander-in-chief Perdiccas. Several other powerful men supported Perdiccas, including
Ptolemy,
Lysimachus,
Peithon
and Eumenes. Perdiccas' power depended on his ability to hold Alexander's enormous empire together, and on whether he could force the
satraps
to obey him.[9]

War soon broke out between Perdiccas and the other
Diadochi. To cement his position, Perdiccas tried to marry Alexander's sister
Cleopatra. The
First War of the Diadochi
began when Perdiccas sent Alexander's corpse to Macedonia for burial. Ptolemy however captured the body and took it to Alexandria. Perdiccas and his troops followed him to Egypt, whereupon Ptolemy conspired with the satrap of Media,
Peithon, and the commander of the
Argyraspides,
Antigenes, both serving as officers under Perdiccas, and assassinated him.
Cornelius Nepos
mentions that Seleucus also took part in this conspiracy, but this is not certain.[10]

The most powerful man in the empire after the death of Perdiccas was
Antipater. Perdiccas' opponents gathered in Triparadisos, where the empire of Alexander was partitioned again (the
Treaty of Triparadisus
321 BC).[11]

At Triparadisos the soldiers had become mutinous and were planning to murder their master Antipater. Seleucus and
Antigonus, however, managed to prevent this.[12]
For betraying Perdiccas, Seleucus was awarded the rich province of Babylon. This decision may have been Antigonus' idea. Seleucus' Babylon was surrounded by Peucestas, the satrap of
Persis;
Antigenes, the new satrap of
Susiana
and Peithon of Media. Babylon was one of the wealthiest provinces of the empire, but its military power was insignificant. It is possible that Antipater divided the eastern provinces so that no single satrap could rise above the others in power.[11]

After the death of Alexander,
Archon of Pella
was chosen satrap of Babylon. Perdiccas, however, had had plans to supersede Archon and nominate Docimus
as his successor. During his invasion of Egypt, Perdiccas sent Docimus along with his detachments to Babylon. Archon waged war against him, but fell in battle. Thus, Docimus was not intending to give Babylon to Seleucus without a fight. It is not certain how Seleucus took Babylon from Docimus, but according to one Babylonian chronicle an important building was destroyed in the city during the summer or winter of 320 BC. Other Babylonian sources state that Seleucus arrived in Babylon in October or November 320 BC. Despite the presumed battle, Docimus was able to escape.

Meanwhile, the empire was once again in turmoil. Peithon, the satrap of Media, assassinated Philip, the satrap of
Parthia, and replaced him with his brother
Eudemus
as the new satrap. In the west Antigonus
and Eumenes
waged war against each other. Just like Peithon and Seleucus, Eumenes was one of the former supporters of Perdiccas. Seleucus' biggest problem was, however, Babylon itself. The locals had rebelled against Archon and supported Docimus. The Babylonian priesthood had great influence over the region. Babylon also had a sizable population of Macedonian and Greek veterans of Alexander's army. Seleucus managed to win over the priests with monetary gifts and bribes.[13]

After the death of Antipater in 319 BC, the satrap of Media began to expand his power. Peithon assembled a large army of perhaps over 20,000 soldiers. Under the leadership of Peucestas the other satraps of the region brought together an opposing army of their own. Peithon was finally defeated in a battle waged in Parthia. He escaped to Media, but his opponents did not follow him and rather returned to Susiana. Meanwhile, Eumenes and his army had arrived at
Cilicia, but had to retreat when Antigonus reached the city. The situation was difficult for Seleucus. Eumenes and his army were north of Babylon; Antigonus was following him with an even larger army; Peithon was in Media and his opponents in Susiana. Antigenes, satrap of Susiana and commander of the Argyraspides, was allied with Eumenes. Antigenes was in Cilicia when the war between him and Peithon began.[14]

Peithon arrived at Babylon in the autumn or winter of 317 BC. Peithon had lost a large number of troops, but Seleucus had even fewer soldiers. Eumenes decided to march to Susa in the spring of 316 BC. The satraps in Susa had apparently accepted Eumenes' claims of his fighting on behalf of the lawful ruling family against the usurper Antigonus. Eumenes marched his army 300
stadions
away from Babylon and tried to cross the Tigris. Seleucus had to act. He sent two
triremes
and some smaller ships to stop the crossing. He also tried to get the former hypasiti
of the Argyraspides to join him, but this did not happen. Seleucus also sent messages to Antigonus. Because of his lack of troops, Seleucus apparently had no plans to actually stop Eumenes. He opened the flood barriers of the river, but the resulting flood did not stop Eumenes.[15]

In the spring of 316 BC, Seleucus and Peithon joined Antigonus, who was following Eumenes to Susa. From Susa Antigonus went to Media, from where he could threaten the eastern provinces. He left Seleucus with a small number of troops to prevent Eumenes from reaching the Mediterranean.
Sibyrtius, satrap of
Arachosia, saw the situation as hopeless and returned to his own province. The armies of Eumenes and his allies were at breaking point. Antigonus and Eumenes had two encounters during 316 BC, in the battles of
Paraitacene
and Gabiene. Eumenes was defeated and executed. The events of the Second War of the Diadochi revealed Seleucus' ability to wait for the right moment. Blazing into battle was not his style.[16]

Antigonus spent the winter of 316 BC in Media, whose ruler was once again Peithon. Peithon's lust for power had grown, and he tried to get a portion of Antigonus' troops to revolt to his side. Antigonus, however, discovered the plot and executed Peithon. He then superseded Peucestas as satrap of Persia.[17]
In the summer of 315 BC Antigonus arrived in Babylon and was warmly welcomed by Seleucus. The relationship between the two soon turned cold, however. Seleucus punished one of Antigonus' officers without asking permission from Antigonus. Antigonus became angry and demanded that Seleucus give him the income from the province, which Seleucus refused to do.[18]
He was, however, afraid of Antigonus and fled to Egypt with 50 horsemen. It is told that Chaldean
astrologers prophesied to Antigonus that Seleucus would become master of Asia and would kill Antigonus. After hearing this, Antigonus sent soldiers after Seleucus, who had however first escaped to Mesopotamia
and then to Syria. Antigonus executed Blitor, the new satrap of Mesopotamia, for helping Seleucus. Modern scholars are skeptical of the prophecy story. It seems certain, however, that the Babylon priesthood was against Seleucus.[19]

During Seleucus' escape to Egypt, Macedonia was undergoing great turmoil. Alexander the Great's mother
Olympias
had been invited back to Macedon by Polyperchon
in order to drive Cassander out. She held great respect among the Macedonian army but lost some of this when she had Philip III and his wife Eurydice
killed as well as many nobles whom she took revenge upon for supporting Antipater during his long reign. Cassander
reclaimed Macedon the following year at Pydna and then had her killed. Alexander IV, still a young child, and his mother Roxane were held guarded at Amphipolis and died under mysterious circumstances in 310 BC, probably murdered at the instigation of
Cassander
to allow the diadochs to assume the title of king.

After arriving in Egypt, Seleucus sent his friends to Greece to inform Cassander and Lysimachus, the ruler of
Thracia, about Antigonus. Antigonus was now the most powerful of the
Diadochi, and the others would soon ally against him. The allies sent a proposition to Antigonus in which they demanded that Seleucus be allowed to return to Babylon. Antigonus refused and went to Syria, where he planned to attack Ptolemy in the spring of 314 BC.[20]
Seleucus was an admiral under Ptolemy. At the same time he started the siege of Tyros,[21]
Antigonus allied with Rhodes. The island had a strategic location and its navy was capable of preventing the allies from combining their forces. Because of the threat of Rhodes, Ptolemy gave Seleucus a hundred ships and sent him to the Aegean Sea. The fleet was too small to defeat Rhodes, but it was big enough to force
Asander, the satrap of
Caria, to ally with Ptolemy. To demonstrate his power, Seleucus also invaded the city of
Erythrai. Ptolemy, nephew of Antigonus, attacked Asander. Seleucus returned to Cyprus, where Ptolemy I had sent his brother
Menelaos
along with 10,000 mercenaries and 100 ships. Seleucus and Menelaos began to besiege Kition. Antigonus sent most of his fleet to the Aegean Sea and his army to Asia Minor. Ptolemy now had an opportunity to invade Syria, where he defeated Demetrius, the son of Antigonus, in the
battle of Gaza
in 312 BC. It is probable that Seleucus took part in the battle. Peithon, son of Agenor, whom Antigonus had nominated as the new satrap of Babylon, fell in the battle. The death of Peithon gave Seleucus an opportunity to return to Babylon.[22]

Seleucus had prepared his return to Babylon well. After the battle of Gaza Demetrius retreated to
Tripoli
while Ptolemy advanced all the way to Sidon. Ptolemy gave Seleucus 800 infantry and 200 cavalry. He also had his friends accompanying him, perhaps the same 50 who escaped with him from Babylon. On the way to Babylon Seleucus recruited more soldiers from the colonies along the route. He finally had about 3,000 soldiers. In Babylon, Peithon's commander, Diphilus, barricaded himself in the city's fortress. Seleucus conquered Babylon with great speed and the fortress was also quickly captured. Seleucus' friends who had stayed in Babylon were released from captivity.[23]
His return to Babylon was afterwards officially regarded as the beginning of the Seleucid Empire
and that year as the first of the Seleucid era.

Soon after Seleucus' return, the supporters of Antigonus tried to get Babylon back.
Nicanor
was the new satrap of Media and the strategos
of the eastern provinces. His army had about 17,000 soldiers. Evagoras, the satrap of Aria, was allied with him. It was obvious that Seleucus' small force could not defeat the two in battle. Seleucus hid his armies in the marshes that surrounded the area where Nicanor was planning to cross the Tigris and made a surprise attack during the night. Evagoras fell in the beginning of the battle and Nicanor was cut off from his forces. The news about the death of Evagoras spread among the soldiers, who started to surrender
en masse. Almost all of them agreed to fight under Seleucus. Nicanor managed to escape with only a few men.[24]

Even though Seleucus now had about 20,000 soldiers, they were not enough to withstand the forces of Antigonus. He also did not know when Antigonus would begin his counterattack. On the other hand, he knew that at least two eastern provinces did not have a satrap. A great majority of his own troops were from these provinces. Some of Evagoras' troops were Persian. Perhaps a portion of the troops were Eumenes' soldiers, who had a reason to hate Antigonus. Seleucus decided to take advantage of this situation.[24]

Seleucus spread different stories among the provinces and the soldiers. According to one of them, he had in a dream seen Alexander standing beside him. Eumenes had tried to use a similar propaganda trick. Antigonus, who had been in Asia Minor while Seleucus had been in the east with Alexander, could not use Alexander in his own propaganda. Seleucus, being Macedonian, had the ability to gain the trust of the Macedonians among his troops, which was not the case with Eumenes.[25]

After becoming once again satrap of Babylon, Seleucus became much more aggressive in his politics. In a short time he conquered Media and Susiana.
Diodorus Siculus
reports that Seleucus also conquered other nearby areas, which might refer to Persis,
Aria
or Parthia. Seleucus did not reach
Bactria
and Sogdiana. The satrap of the former was
Stasanor, who had managed to remain neutral during the conflicts. After the defeat of Nikanor's army, there was no force in the east that could have opposed Seleucus. It is uncertain how Seleucus arranged the administration of the provinces he had conquered. Most satraps had died. In theory,
Polyperchon
was still the lawful successor of Antipater and the official regent of the Macedonian kingdom. It was his duty to select the satraps. However, Polyperchon was still allied with Antigonus and thus an enemy of Seleucus.[26]

Antigonus sent his son Demetrius along with 15,000 infantry and 4,000 cavalry to reconquer Babylon. Apparently, he gave Demetrius a time limit, after which he had to return to Syria. Antigonus believed Seleucus was still ruling only Babylon. Perhaps Nicanor had not told him that Selucus now had at least 20,000 soldiers. It seems that the scale of Nicanor's defeat was not clear to all parties. Antigonus did not know Seleucus had conquered the majority of the eastern provinces and perhaps cared little about the eastern parts of the empire.[27]

When Demetrius arrived in Babylon, Seleucus was somewhere in the east. He had left
Patrocles
to defend the city. Babylon was defended in an unusual way. It had two strong fortresses, in which Seleucus had left his garrisons. The inhabitants of the city were transferred out and settled in the neighboring areas, some as far as Susa. The surroundings of Babylon were excellent for defense, with cities, swamps, canals and rivers. Demetrius' troops started to besiege the fortresses of Babylon and managed to conquer one of them. The second fortress proved more difficult for Demetrius. He left his friend Archelaus to continue the siege, and himself returned west leaving 5,000 infantry and 1,000 cavalry in Babylon. Ancient sources do not mention what happened to these troops. Perhaps Seleucus had to reconquer Babylon from Archelaus.[28]

Over the course of nine years (311–302 BC), while Antigonus was occupied in the west, Seleucus brought the whole eastern part of Alexander's empire as far as the
Jaxartes
and Indus Rivers
under his authority.

In 311 BC Antigonus made peace with Cassander, Lysimachus and Ptolemy, which gave him an opportunity to deal with Seleucus.[29]
Antigonus' army had at least 80,000 soldiers. Even if he left half of his troops in the west, he would still have a numerical advantage over Seleucus. Seleucus may have received help from Cossaians, whose ancestors were the ancient Kassites. Antigonus had devastated their lands while fighting Eumenes. Seleucus perhaps recruited a portion of Archelaus' troops. When Antigonus finally invaded Babylon, Seleucus' army was much bigger than before. Many of his soldiers certainly hated Antigonus. The population of Babylon was also hostile. Seleucus, thus, did not need to garrison the area to keep the locals from revolting.[30]

Little information is available about the conflict between Antigonus and Seleucus; only a very rudimentary Babylonian chronicle detailing the events of the war remains. The description of the year 310 BC has completely disappeared. It seems that Antigonus managed to conquer Babylon. His plans were disturbed, however, by Ptolemy, who made a surprise attack in Cilicia.[30]

We do know that Seleucus managed to defeat Antigonus in at least one decisive battle. This battle is only mentioned in
Stratagems in War
by Polyaenus. Polyaenus reports that the troops of Seleucus and Antigonus fought for a whole day, but when night came the battle was still undecided. The two forces agreed to rest for the night and continue in the morning. Antigonus' troops slept without their equipment. Seleucus ordered his forces to sleep and eat breakfast in battle formation. Shortly before dawn, Seleucus' troops attacked the forces of Antigonus, who were still without their weapons and in disarray and thus easily defeated. The historical accuracy of the story is questionable.[31][32]

The Babylonian war finally ended in Seleucus' victory. Antigonus was forced to retreat west. Both sides fortified their borders. Antigonus built a series of fortresses along the
Balikh River
while Seleucus built a few cities, including Dura-Europos
and Nisibis.

The next event connected to Seleucus was the founding of the city of
Seleucia. The city was built on the shore of the Tigris probably in 307 or 305 BC. Seleucus made Seleucia his new capital, thus imitating Lysimachus, Cassander and Antigonus, all of whom had named cities after themselves. Seleucus also transferred the mint of Babylon to his new city. Babylon was soon left in the shadow of Seleucia, and the story goes that
Antiochus, the son of Seleucus, moved the whole population of Babylon to his father's namesake capital in 275 BC. The city flourished until AD 165, when the Romans destroyed it.[31][33]

A story of the founding of the city goes as follows: Seleucus asked the Babylonian priests which day would be best to found the city. The priest calculated the day, but, wanting the founding to fail, told Seleucus a different date. The plot failed however, because when the correct day came, Seleucus' soldiers spontaneously started to build the city. When questioned, the priests admitted their deed.[34]

The struggle among the Diadochi reached its climax when Antigonus, after the extinction of the old royal line of Macedonia, proclaimed himself king in 306 BC. Ptolemy, Lysimachus, Cassander and Seleucus soon followed. Also,
Agathocles
of Sicily declared himself king around the same time.[31][35]
Seleucus, like the other four principal Macedonian chiefs, assumed the title and style of basileus
(king).

Seleucus soon turned his attention once again eastward. In the year 305 BC, Seleucus I Nicator went to India and apparently occupied territory as far as the Indus, and eventually
waged war
with the Maurya
Emperor Chandragupta Maurya:

Always lying in wait for the neighboring nations, strong in arms and persuasive in council, he [Seleucus] acquired Mesopotamia, Armenia, 'Seleucid' Cappadocia, Persis, Parthia, Bactria, Arabia, Tapouria, Sogdia, Arachosia, Hyrcania, and other adjacent peoples that had been subdued by Alexander, as far as the river Indus, so that the boundaries of his empire were the most extensive in Asia after that of Alexander. The whole region from Phrygia to the Indus was subject to Seleucus. He crossed the Indus and waged war with
Sandrocottus, king of the Indians, who dwelt on the banks of that stream, until they came to an understanding with each other and contracted a marriage relationship. –
Appian, History of Rome, The
Syrian Wars
55[36]

Only a few sources mention his activities in India. Chandragupta (known in Greek sources as
Sandrokottos), founder of the
Mauryan empire, had conquered the Indus valley and several other parts of the easternmost regions of Alexander's empire. Seleucus began a campaign against Chandragupta and crossed the
Indus.[37]
Seleucus' Indian campaign was, however, a failure. It is unknown what exactly happened. Perhaps Chandragupta defeated Seleucus in battle. No sources mention this, however. But as most western historians note, Seleucus appears to have fared poorly as he did not achieve his aims. The two leaders ultimately reached an agreement, and through a treaty sealed in 305 BC,[38]
Seleucus ceded a considerable amount of territory to Chandragupta in exchange for 500 war elephants, which were to play a key role in the forthcoming battles, particularly at Ipsus.[39]
The victorious Maurya king probably married the daughter of his Greek rival.[40]
According to Strabo, the ceded territories bordered the Indus:

The geographical position of the tribes is as follows: along the Indus are the Paropamisadae, above whom lies the Paropamisus mountain: then, towards the south, the Arachoti: then next, towards the south, the Gedroseni, with the other tribes that occupy the seaboard; and the Indus lies, latitudinally, alongside all these places; and of these places, in part, some that lie along the Indus are held by Indians, although they formerly belonged to the Persians. Alexander [III 'the Great' of Macedon] took these away from the Arians and established settlements of his own, but
Seleucus Nicator
gave them to Sandrocottus
[Chandragupta], upon terms of intermarriage and of receiving in exchange five hundred elephants. — Strabo 15.2.9[41]

From this, it seems that Seleucus surrendered the easternmost provinces of
Arachosia,
Gedrosia,
Paropamisadae
and perhaps also Aria. On the other hand, he was accepted by other satraps of the eastern provinces. His Persian wife, Apama, may have helped him implement his rule in
Bactria
and Sogdiana. Mainstream scholarship asserts that Chandragupta received vast territory west of the Indus, including the
Hindu Kush, modern-day
Afghanistan, and the
Balochistan, presently in
Pakistan.[42][43]
This would tend to be corroborated archaeologically, as concrete indications of Mauryan influence, such as the inscriptions of the Edicts of Ashoka
which are known to be located in, for example, Kandhahar
in today's southern Afghanistan. However, Ashoka's Edicts were inscribed two generations after any territorial handover by Seleucus and, for this reason, it is equally possible that the land in which these Edicts are to be found was incorporated into the Mauryan empire by Bindusara, Chandragupta's son and successor, or Ashoka himself.

Some authors claim that the argument relating to Seleucus handing over more of what is now southern Afghanistan is an exaggeration originating in a statement by Pliny the Elder referring not specifically to the lands received by Chandragupta, but rather to the various opinions of geographers regarding the definition of the word "India":[44]

Most geographers, in fact, do not look upon India as bounded by the river Indus, but add to it the four satrapies of the
Gedrose, the
Arachotë, the
Aria, and the
Paropamisadë, the
River Cophes
thus forming the extreme boundary of India. According to other writers, however, all these territories, are reckoned as belonging to the country of the Aria. — Pliny, Natural History VI, 23[45]

Nevertheless, it is usually considered today that Arachosia and the other three regions did become dominions of the Mauryan Empire.

The alliance between Chandragupta and Seleucus was affirmed with a marriage (Epigamia). Chandragupta or his son married a daughter of Seleucus, Cornelia, or perhaps there was diplomatic recognition of intermarriage between Indians and Greeks.An Indian
Puranic
source, the Pratisarga Parva
of the Bhavishya Purana, also described the marriage of
Chandragupta
with a Greek ("Yavana") princess, daughter of Seleucus (Suluva[46]
in Indian sources).[47]

In addition to this matrimonial recognition or alliance, Seleucus dispatched an ambassador,
Megasthenes, to the Mauryan court at
Pataliputra
(Modern Patna
in Bihar state).[48]
Only short extracts remain of Megasthenes' description of the journey.[38]

The two rulers seem to have been on very good terms, as classical sources have recorded that following their treaty, Chandragupta sent various presents such as
aphrodisiacs
to Seleucus.[49][50]

Seleucus obtained knowledge of most of northern India, as explained by
Pliny the Elder
through his numerous embassies to the Mauryan Empire:

The Hellenistic world view after Seleucus: ancient world map
of Eratosthenes
(276–194 BC), incorporating information from the campaigns of Alexander and his successors[51]

The other parts of the country [beyond the
Hydaspes, the farthest extent of Alexander's conquests] were discovered and surveyed by Seleucus Nicator: namely

and so to the mouth of the Ganges where he falleth into the sea 638 miles. — Pliny the Elder, Natural history, Book 6, Chap 21[52]

Seleucus apparently minted coins during his stay in India, as several coins in his name are in the Indian standard and have been excavated in India. These coins describe him as "Basileus" ("King"), which implies a date later than 306 BC. Some of them also mention Seleucus in association with his son Antiochus as king, which would also imply a date as late as 293 BC. No Seleucid coins were struck in India thereafter and confirm the reversal of territory west of the Indus to Chandragupta.[53]

Seleucus may have founded a navy in the
Persian Gulf
and in the Indian Ocean.[31]

Tetradrachm of Seleucus from Seleucia. Obverse: the head of Zeus, Reverse:
Athena
with elephants

The war elephants Seleucus received from Chandragupta proved to be useful when the Diadochi finally decided to deal with Antigonus. Cassander, Seleucus and Lysimachus defeated Antigonus and Demetrius in the
battle of Ipsus. Antigonus fell in battle, but Demetrius managed to escape. After the battle, Syria was placed under Seleucus' rule. He understood Syria to encompass the region from the
Taurus mountains
to Sinai, but Ptolemy had already conquered
Palestine
and Phoenicia. In 299 BC, Seleucus allied with Demetrius and married his daughter
Stratonice. Stratonice was also the daughter of Antipater's daughter
Phila. Seleucus had a daughter by Stratonice, who was also called
Phila.[54]

The fleet of Demetrius managed to destroy Ptolemy's fleet and thus Seleucus did not need to fight him.[55]

Seleucus, however, did not manage to enlarge his kingdom to the west. The main reason was that he did not have enough Greek and Macedonian troops. During the battle of Ipsus, he had less infantry than Lysimachus. His strength was in his war elephants and in traditional Persian cavalry. In order to enlarge his army, Seleucus tried to attract colonists from mainland Greece by founding four new cities—Seleucia Pieria
and Laodicea in Syria
on the coast and Antioch on the Orontes
and Apameia
in the Orontes River
valley. Antioch
became his chief seat of government. The new Seleucia was supposed to become his new naval base and a gateway to the Mediterranean. Seleucus also founded six smaller cities.[55]

It is said of Seleucus that "few princes have ever lived with so great a passion for the building of cities. He is reputed to have built in all nine Seleucias, sixteen Antiochs, and six Laodiceas".[56]

Seleucus nominated his son
Antiochus I
as his co-ruler and viceroy of the eastern provinces in 292 BC, the vast extent of the empire seeming to require a double government. In 294 BC Stratonice married her stepson Antiochus. Seleucus reportedly instigated the marriage after discovering that his son was in danger of dying of lovesickness.[57]
Seleucus was thus able to get Stratonice out of the way, as her father Demetrius had now become king of Macedonia.

The alliance between Seleucus and Demetrius ended in 294 BC when Seleucus conquered
Cilicia. Demetrius invaded and easily conquered Cilicia in 286 BC, which meant that Demetrius was now threatening the most important regions of Seleucus' empire in Syria. Demetrius' troops, however, were tired and had not received their payment. Seleucus, on the other hand, was known as a cunning and rich leader who had earned the adoration of his soldiers. Seleucus blocked the roads leading south from Cilicia and urged Demetrius' troops to join his side. Simultaneously he tried to evade battle with Demetrius. Finally, Seleucus addressed Demetrius personally. He showed himself in front of the soldiers and removed his helmet, revealing his identity. Demetrius' troops now started to abandon their leader
en masse. Demetrius was finally imprisoned in Apameia and died a few years later in captivity.[55]

Lysimachus and Ptolemy had supported Seleucus against Demetrius, but after the latter's defeat the alliance started to break apart. Lysimachus ruled Macedonia,
Thracia
and Asia Minor. He also had problems with his family. Lysimachus executed his son
Agathocles, whose wife
Lysandra
escaped to Babylon to Seleucus.[55]

The unpopularity of Lysimachus after the murder of
Agathocles
gave Seleucus an opportunity to remove his last rival. His intervention in the west was solicited by Ptolemy Keraunos, who, on the accession to the Egyptian throne of his brother
Ptolemy II
(285 BC), had at first taken refuge with Lysimachus and then with Seleucus. Seleucus then invaded Asia Minor and defeated his rival in the Battle of Corupedium
in Lydia, 281 BC. Lysimachus fell in battle. In addition, Ptolemy had died a few years earlier. Seleucus was thus now the only living contemporary of Alexander.[55]

Before his death, Seleucus tried to deal with the administration of Asia Minor. The region was ethnically diverse, consisting of Greek cities, a Persian aristocracy and indigenous peoples. Seleucus perhaps tried to defeat
Cappadocia, but failed. Lysimachus' old officer
Philetairos
ruled Pergamon
independently. On the other hand, based on their names, Seleucus apparently founded a number of new cities in Asia Minor.[55]

Few of the letters Seleucus sent to different cities and temples still exist. All cities in Asia Minor sent embassies to their new ruler. It is reported that Seleucus complained about the number of letters he received and was forced to read. He was apparently a popular ruler. In
Lemnos
he was celebrated as a liberator and a temple was built to honour him. According to a local custom, Seleucus was always offered an extra cup of wine during dinner time. His title during this period was Seleucus Soter
("savior"). When Seleucus left for Europe, the organizational rearrangement of Asia Minor had not been completed.[55]

Seleucus now held the whole of Alexander's conquests except Egypt and moved to take possession of Macedonia and Thrace. He intended to leave Asia to Antiochus and content himself for the remainder of his days with the Macedonian kingdom in its old limits. He had, however, hardly crossed into the
Thracian Chersonese
when he was assassinated by Ptolemy Keraunos
near Lysimachia
in September (281 BC).[citation needed]

It seems certain that after taking Macedonia and Thracia, Seleucus would have tried to conquer Greece. He had already prepared this campaign using the numerous gifts presented to him. He was also nominated an honorary citizen of
Athens.[58]

Antiochus founded the cult of his father. A cult of personality formed around the later members of the Seleucid dynasty and Seleucus was later worshipped as a son of god[clarification needed]. One inscription found in Ilion (i.e.,
Troy) advises priests to sacrifice to
Apollo, the ancestor of Antiochus' family. Several anecdotes of Seleucus' life became popular in the classical world.[59]

^Seleucus was given the epithet "Nicator" by later generations which translates into English as "Victor".
Ancient Greek:
Σέλευκος ΝικάτωρSéleukos Nikátōr, "Seleucus the Victor".

^The Diadochi were rival generals, family and friends of Alexander fighting for control of his empire. The word is the plural form of the
Latin
word Diadochus, which comes from the Greek
word Διάδοχοι, diadokhoi, which translates into English as "successors".

^Foreign Influence on Ancient India, Krishna Chandra Sagar, Northern Book Centre, 1992,
p.83. The paragraph of the Pratisarga Parva mentioning this marriage is: "Chandragupta married with a daughter of
Suluva, the
Yavana
king of Pausasa. Thus, he mixed the Buddhists and the Yavanas. He ruled for 60 years. From him,
Vindusara
was born and ruled for the same number of years as his father. His son was Ashoka."Pratisarga Parva p.18. Original Sanskrit of the first two verses: "Chandragupta Sutah Paursadhipateh Sutam. Suluvasya Tathodwahya Yavani Baudhtatapar".

^"And Theophrastus says that some contrivances are of wondrous efficacy in such matters [as to make people more amorous]. And Phylarchus confirms him, by reference to some of the presents which Sandrakottus, the king of the Indians, sent to Seleucus; which were to act like charms in producing a wonderful degree of affection, while some, on the contrary, were to banish love"
Athenaeus of Naucratis,
The Deipnosophists,
i.32